An electronic control unit in which heat generated from a semiconductor module is dissipated to another object such as a heatsink is known. For example, in JP-A-2011-23459 corresponding to U.S. 2011/0013370A1, an electrically-insulating and heat-dissipating sheet or a heat-dissipating gel is placed between a semiconductor module and a heatsink, and heat generated in the semiconductor module is dissipated to the heatsink from the backside.
However, JP-A-2011-23459 does not consider dissipating the heat generated in the semiconductor module to the same side as the board.